Richard Mille just signed a partnership agreement with professional tennis player Rafael Nadal.

To commemorate their relationship, Rafal Nadal worked closely with Richard Mille to develop a tourbillon watch that would be light enough for him to wear while playing tennis.

The result is a new 50 pieces limited edition RM027 watch, which weighs less than 19 grams, including the strap. The most interesting part of this partnership, aside from its lightness, is that Rafael Nadal will wear his $525,000 Richard Mille tourbillon during his matches.